The invention relates to an air discharge system which is operative to discharge air into the compartment of an automobile.
An air conditioner for automobiles is known in the art which draws internal/external atmosphere and adjusts the temperature or humidity thereof before discharging it through an ejection grille which opens into the compartment in order to adjust the temperature or humidity thereof. In consideration of cooling/warming efficiency or air circulation efficiency, it is a general practice to divide an air discharge system into a plurality of sections including a section which directs the air toward the upper half of an occupant who is sitting on a seat and another which directs the air toward his legs. Certain air conditioners which are used for automobiles having a plurality of seats are provided with ejection grilles which are individually associated with the respective seats.
Considering an air conditioner which has an ejection grille associated with each seat, the operational efficiency is of a great importance. Assuming that a four occupant automobile, for example, which includes a front right-hand (hereafter abbreviated as FR), a front left-hand (hereafter abbreviated as FL), a rear right-hand (hereafter abbreviated as RR) and a rear left-hand (hereafter abbreviated as RL) seat, it will be readily seen that unless all of the four occupants seated upon their respective seats, there occurs a discharge of air upon at least one occupant who is actually absent. An ejection grille is normally provided with a fin assembly located on the front thereof which controls the direction of ejection or blocks the opening and which is manually operated. Accordingly, to stop the air ejection upon the absent occupant, another occupant must operate the fin assembly of such ejection grille manually.
To accommodate for such inconvenience, Japanese patent publication No. 20,206/1985 discloses an air conditioner including seating switches associated with the respective seats of an automobile so as to be turned on when they are loaded, the conditioner being operative to detect the presence or absence of an occupant on each seat on the basis of the on/off condition of the seating switches in order to drive a damper disposed within an air duct to control the air flow. With this arrangement, the discharge of air through an ejection grille which is associated with a seat on which no occupant is present is avoided, thus increasing the operational efficiency of the air conditioner.
However, in the air conditioner mentioned above, the use of a seating switch to detect the presence or absence of an occupant on the basis of a loading or weight applied to a seat causes a difficulty that the switch may be turned on if a baggage is placed on the seat. Thus, the seating switch is incapable of distinguishing between a personnel and a baggage, thus resulting in the discharge of air upon a baggage which is placed on the seat. Another problem relates to the durability of the seating switch caused by an excessive loading of the seat which might occur in the boarding process of an occupant or when a child occupant jumps up and down on the seat. If the switch is damaged to remain closed, there results a continued discharge of air upon the location of an occupant which is actually absent. Conversely, if the switch is destroyed in its off condition, no discharge of air upon an actual occupant cannot be achieved.
It is an object of the invention to achieve an increased efficiency of an air discharge system by controlling the discharge operation on the basis of reliable information concerning the presence or absence of an occupant.